The present invention relates to a ring binder for holding a number of punched holed paper sheets, more particularly to a mechanism for locking and unlocking the rings or paper-holding elements of the binder.
Previously ring binders have taken many forms. Typically a fixed one-piece notched spine is provided where the inboard ends of facing rings are connected by an actuating mechanism to finger triggers at opposite ends of the spine which, when pressed, open the facing rings. The binder, after addition or removal of punched-hole paper sheets to or from the rings, is closed by pushing the rings together in a snap-motion. Each of these closing and opening operations take considerable effort and manual finger manipulation, particular when a large number of sheets are in the binder. The rings of prior art binders are normally attached to the actuation mechanism and the trigger linkage is interiorly of the spine. The single spine itself is normally rivet-connected to a portion of the binder cover. The ring binders of the prior art generally use rings or levers to open and close the rings without a positive locking function. Thus, a need has existed to have a ring binder which is easily closed with a minimum of effort, more particularly by only a slight pressure on only one of the ring elements. Likewise a need has existed to provide a ring binder which has a positive ring lock while providing for a slight pressure at one end of the spine to easily effect the opening of the rings.
In the related application, a hinged two-piece spine is provided along with a bridge member therebetween. Locks are provided in the form of a pivotable hook member and pivot link at each end of the spines for locking the spines at a predetermined angle.